ryo-executor 0.1.0

//! MutationRegistry: Central registry for MutationSpec → Mutation conversion
//!
//! The Registry pattern distributes the conversion logic that was previously
//! concentrated in `BlueprintExecutor::convert_and_apply()` (2,400+ lines)
//! into separate Converter implementations.
//!
//! # Architecture
//!
//! ```text
//! MutationSpec
//!    │
//!    ▼ registry.convert(spec)
//! MutationRegistry
//!    ├─ converters: HashMap<kind, Box<dyn MutationConverter>>
//!    │
//!    ▼ find converter by spec.kind_name()
//! MutationConverter (trait)
//!    │
//!    ▼ convert(spec) → Box<dyn Mutation>
//! Mutation
//!    │
//!    ▼ apply(file) → changes
//! ```

mod converter;
pub mod converters;

pub use converter::{
    opt_resolve_file_path_from_symbol, resolve_file_path_from_symbol, ApplyResult, ConvertError,
    MutationConverter, ResolvedMutation,
};

use crate::engine::ASTRegApply;
use crate::executor::spec::MutationSpec;
use ryo_analysis::{AnalysisContext, GraphChecker};
use std::collections::HashMap;

/// Central registry for MutationSpec → Mutation conversion
///
/// Routes each MutationSpec to its appropriate Converter based on kind_name().
pub struct MutationRegistry {
    converters: HashMap<&'static str, Box<dyn MutationConverter>>,
}

impl std::fmt::Debug for MutationRegistry {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("MutationRegistry")
            .field("registered_kinds", &self.registered_kinds())
            .finish()
    }
}

impl MutationRegistry {
    /// Create a new registry with all built-in converters registered
    ///
    /// Uses `register_all()` for converters that handle multiple spec kinds,
    /// which automatically registers all kinds from `spec_kinds()`.
    /// This prevents the "forgot to register" bug.
    pub fn new() -> Self {
        let mut registry = Self {
            converters: HashMap::new(),
        };

        // Phase 1: Basic converters (single or few kinds)
        registry.register("Rename", Box::new(converters::RenameConverter::new()));
        registry.register(
            "ChangeVisibility",
            Box::new(converters::VisibilityConverter::new()),
        );
        registry.register_all::<converters::FieldConverter>(); // AddField, RemoveField
        registry.register_all::<converters::DeriveConverter>(); // AddDerive, RemoveDerive

        // Phase 2: Complex converters
        registry.register_all::<converters::EnumConverter>(); // AddVariant, RemoveVariant
        registry.register("RemoveItem", Box::new(converters::RemoveConverter::new()));
        registry.register_all::<converters::MethodConverter>(); // AddMethod, RemoveMethod
        registry.register_all::<converters::ModuleConverter>(); // AddMod, RemoveMod, CreateMod
        registry.register("AddItem", Box::new(converters::AddItemConverter::new()));

        // Phase 3: Idiom converters (15 variants - biggest win!)
        registry.register_all::<converters::IdiomConverter>();

        // Phase 3: Other converters
        registry.register_all::<converters::TraitConverter>(); // ExtractTrait, InlineTrait
        registry.register("MoveItem", Box::new(converters::MoveConverter::new()));
        registry.register(
            "PluginTransform",
            Box::new(converters::PluginConverter::new()),
        );
        registry.register_all::<converters::StmtConverter>(); // ReplaceExpr, RemoveStatement, etc.
        registry.register_all::<converters::MatchArmConverter>(); // AddMatchArm, RemoveMatchArm
        registry.register_all::<converters::StructLiteralFieldConverter>(); // Add/RemoveStructLiteralField
        registry.register_all::<converters::DuplicateConverter>(); // DuplicateFunction, etc.

        registry
    }

    /// Register a converter for a single spec kind
    ///
    /// Note: Each spec kind can only have one converter.
    /// For converters handling multiple spec kinds, use `register_all()`.
    pub fn register(&mut self, kind: &'static str, converter: Box<dyn MutationConverter>) {
        self.converters.insert(kind, converter);
    }

    /// Register a converter for all its spec_kinds() automatically.
    ///
    /// This method creates a new instance of the converter for each spec kind
    /// it handles. Requires the converter to implement `Default`.
    ///
    /// # Example
    ///
    /// ```ignore
    /// // Instead of:
    /// registry.register("FilterNext", Box::new(IdiomConverter::new()));
    /// registry.register("MapUnwrapOr", Box::new(IdiomConverter::new()));
    /// // ... 15 more lines
    ///
    /// // Use:
    /// registry.register_all::<IdiomConverter>();
    /// ```
    pub fn register_all<C: MutationConverter + Default + 'static>(&mut self) {
        let temp = C::default();
        for kind in temp.spec_kinds() {
            self.converters.insert(*kind, Box::new(C::default()));
        }
    }

    /// Check if this registry can handle the given spec
    pub fn can_handle(&self, spec: &MutationSpec) -> bool {
        self.converters.contains_key(spec.kind_name())
    }

    /// Get the converter for a spec, if registered
    pub fn get(&self, spec: &MutationSpec) -> Option<&dyn MutationConverter> {
        self.converters.get(spec.kind_name()).map(|c| c.as_ref())
    }

    /// Convert a MutationSpec to a Mutation (DEPRECATED)
    #[deprecated(
        since = "0.1.0",
        note = "Returns Box<dyn Mutation> for legacy apply(&mut PureFile). Use convert_v2() for ASTRegApply."
    )]
    #[allow(deprecated)]
    pub fn convert(
        &self,
        spec: &MutationSpec,
    ) -> Result<Box<dyn ryo_mutations::Mutation>, ConvertError> {
        let converter = self
            .converters
            .get(spec.kind_name())
            .ok_or_else(|| ConvertError::UnknownSpec(spec.kind_name().to_string()))?;

        converter.convert(spec)
    }

    /// Convert a MutationSpec to execution units (V2 API)
    ///
    /// Returns a vector of ASTRegApply mutations that implement the spec.
    /// One spec may expand to multiple execution units.
    ///
    /// # Returns
    ///
    /// - `Ok(mutations)` - Vector of mutations to execute
    /// - `Err(V2NotSupported)` - Converter doesn't implement convert_v2 yet
    /// - `Err(UnknownSpec)` - No converter registered for this spec kind
    pub fn convert_v2(
        &self,
        spec: &MutationSpec,
        ctx: &AnalysisContext,
    ) -> Result<Vec<Box<dyn ASTRegApply>>, ConvertError> {
        let converter = self
            .converters
            .get(spec.kind_name())
            .ok_or_else(|| ConvertError::UnknownSpec(spec.kind_name().to_string()))?;

        converter.convert_v2(spec, ctx)
    }

    /// Pre-check a MutationSpec before applying.
    ///
    /// Uses GraphChecker to validate that targets exist before mutation.
    /// This catches errors early (e.g., field not found, type not found)
    /// without running `cargo check`.
    ///
    /// # Checks performed
    ///
    /// | Spec Kind | Check |
    /// |-----------|-------|
    /// | Rename | Target symbol exists |
    /// | AddField/RemoveField | Struct exists |
    /// | AddDerive/RemoveDerive | Target type exists |
    /// | AddVariant/RemoveVariant | Enum exists |
    /// | AddMethod/RemoveMethod | Target type exists |
    /// | ChangeVisibility | Target exists |
    pub fn pre_check(
        &self,
        spec: &MutationSpec,
        ctx: &AnalysisContext,
    ) -> Result<(), ConvertError> {
        let _checker = GraphChecker::new(ctx.code_graph(), ctx.typeflow_graph(), ctx.registry());

        match spec {
            // === Symbol existence and uniqueness checks ===
            // symbol_id is now required, so we trust it (O(1) access).
            // No uniqueness check needed.
            MutationSpec::Rename { .. } => {}

            // AddField/RemoveField: symbol_id is required, no uniqueness check needed
            MutationSpec::AddField { .. } | MutationSpec::RemoveField { .. } => {}

            // AddDerive/RemoveDerive: symbol_id is required, no uniqueness check needed
            MutationSpec::AddDerive { .. } | MutationSpec::RemoveDerive { .. } => {}

            // AddVariant: symbol_id is required, no uniqueness check needed
            MutationSpec::AddVariant { .. } => {}

            // RemoveVariant: symbol_id is required, no uniqueness check needed
            MutationSpec::RemoveVariant { .. } => {}

            MutationSpec::AddMethod {
                target: target_symbol,
                ..
            } => {
                // AddMethod uses target_symbol: MutationTargetSymbol (lazy resolution)
                // Pre-check validation happens at converter level
                let _ = target_symbol; // Suppress unused warning
            }

            MutationSpec::RemoveMethod { .. } => {
                // SymbolId is required, no name-based pre-check needed
            }

            MutationSpec::ChangeVisibility { .. } => {
                // SymbolId is required, no name-based pre-check needed
            }

            // === Mutations that don't need pre-check ===
            // SymbolId is required for RemoveItem, no name-based pre-check needed
            MutationSpec::RemoveItem { .. } => {
                // SymbolId is required, no name-based pre-check needed
            }

            // These create new items or operate on files directly
            MutationSpec::AddItem { .. }
            | MutationSpec::RemoveMod { .. }
            | MutationSpec::CreateMod { .. }
            | MutationSpec::AddSpec { .. }
            | MutationSpec::AddMatchArm { .. }
            | MutationSpec::RemoveMatchArm { .. }
            | MutationSpec::ReplaceMatchArm { .. }
            | MutationSpec::AddStructLiteralField { .. }
            | MutationSpec::RemoveStructLiteralField { .. } => {
                // No pre-check needed
            }

            // === Idiom transformations ===
            // These operate on code patterns, not specific symbols
            MutationSpec::OrganizeImports { .. }
            | MutationSpec::LoopToIterator { .. }
            | MutationSpec::UnwrapToQuestion { .. }
            | MutationSpec::AssignOp { .. }
            | MutationSpec::BoolSimplify { .. }
            | MutationSpec::CloneOnCopy { .. }
            | MutationSpec::CollapsibleIf { .. }
            | MutationSpec::ComparisonToMethod { .. }
            | MutationSpec::RedundantClosure { .. }
            | MutationSpec::IntroduceVariable { .. }
            | MutationSpec::ManualMap { .. }
            | MutationSpec::MatchToIfLet { .. }
            | MutationSpec::FilterNext { .. }
            | MutationSpec::MapUnwrapOr { .. } => {
                // No pre-check for idiom transformations
            }

            // === Spec operations ===
            MutationSpec::RemoveSpec { .. } => {
                // SymbolId is required, no name-based pre-check needed
            }

            MutationSpec::ValidateSpec { .. } => {
                // ValidateSpec is read-only, no pre-check needed
            }

            // === Other mutations ===
            MutationSpec::ExtractTrait { .. }
            | MutationSpec::InlineTrait { .. }
            | MutationSpec::ReplaceType { .. }
            | MutationSpec::EnumToTrait { .. }
            | MutationSpec::MoveItem { .. }
            | MutationSpec::PluginTransform { .. }
            | MutationSpec::ReplaceExpr { .. }
            | MutationSpec::RemoveStatement { .. }
            | MutationSpec::InsertStatement { .. }
            | MutationSpec::ReplaceStatement { .. }
            | MutationSpec::DuplicateFunction { .. }
            | MutationSpec::DuplicateStruct { .. }
            | MutationSpec::DuplicateEnum { .. }
            | MutationSpec::DuplicateModTree { .. }
            | MutationSpec::NoOpArmToTodo { .. } => {
                // No pre-check for these (or could be added later)
            }
        }

        Ok(())
    }

    /// Get the number of registered converters
    pub fn len(&self) -> usize {
        self.converters.len()
    }

    /// Check if the registry is empty
    pub fn is_empty(&self) -> bool {
        self.converters.is_empty()
    }

    /// Get all registered spec kinds
    pub fn registered_kinds(&self) -> Vec<&'static str> {
        self.converters.keys().copied().collect()
    }
}

impl Default for MutationRegistry {
    fn default() -> Self {
        Self::new()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_registry_has_all_converters() {
        let registry = MutationRegistry::new();
        // All phases converters are registered
        assert!(!registry.is_empty());
        // Phase 1: Rename, AddField, RemoveField, ChangeVisibility, AddDerive, RemoveDerive (6)
        // Phase 2: AddVariant, RemoveVariant, RemoveItem, AddMethod, RemoveMethod,
        //          RemoveMod, CreateMod, AddItem (8) - Note: AddMod was consolidated into CreateMod
        // Phase 3: 15 Idiom + 3 Trait (ExtractTrait, InlineTrait, EnumToTrait) + 1 Move + 1 Plugin
        //          + 4 Stmt + 2 MatchArm + 2 StructLiteral + 4 Duplicate + 1 Default = 33
        // Note: AddSpec is handled via Blueprint composition, not a direct converter
        // Note: MergeImplBlocks removed - RegistryGenerator auto-merges impl blocks
        // Total spec kinds handled: 6 + 8 + 33 = 47
        assert_eq!(registry.len(), 47);
    }

    #[test]
    fn test_registry_can_handle_rename() {
        use ryo_symbol::{SymbolKind, SymbolPath, SymbolRegistry};

        let registry = MutationRegistry::new();
        let mut sym_registry = SymbolRegistry::new();
        let path = SymbolPath::parse("test_crate::old").unwrap();
        let symbol_id = sym_registry.register(path, SymbolKind::Function).unwrap();

        let spec = MutationSpec::Rename {
            target: crate::executor::spec::MutationTargetSymbol::ById(symbol_id),
            to: "new".into(),
            scope: crate::executor::spec::Scope::Project,
        };

        assert!(registry.can_handle(&spec));
    }

    #[test]
    fn test_registry_can_handle_field() {
        use ryo_symbol::{SymbolKind, SymbolPath, SymbolRegistry};

        let registry = MutationRegistry::new();
        let mut sym_registry = SymbolRegistry::new();
        let path = SymbolPath::parse("test_crate::Config").unwrap();
        let symbol_id = sym_registry.register(path, SymbolKind::Struct).unwrap();

        let add_spec = MutationSpec::AddField {
            target: crate::executor::spec::MutationTargetSymbol::ById(symbol_id),
            field_name: "timeout".into(),
            field_type: "u64".into(),
            visibility: crate::executor::spec::Visibility::Pub,
        };
        assert!(registry.can_handle(&add_spec));

        let remove_spec = MutationSpec::RemoveField {
            target: crate::executor::spec::MutationTargetSymbol::ById(symbol_id),
            field_name: "timeout".into(),
        };
        assert!(registry.can_handle(&remove_spec));
    }

    #[test]
    fn test_registry_can_handle_add_item() {
        let registry = MutationRegistry::new();

        // AddItem is registered (Phase 2)
        let spec = MutationSpec::AddItem {
            target: crate::executor::spec::MutationTargetSymbol::ByPath(Box::new(
                crate::executor::spec::SymbolPath::parse("test_crate::lib").unwrap(),
            )),
            content: "struct Foo {}".into(),
            position: crate::executor::spec::InsertPosition::Top,
        };
        assert!(registry.can_handle(&spec));
    }

    #[test]
    fn test_registry_registered_kinds() {
        let registry = MutationRegistry::new();
        let kinds = registry.registered_kinds();

        assert!(kinds.contains(&"Rename"));
        assert!(kinds.contains(&"AddField"));
        assert!(kinds.contains(&"RemoveField"));
        assert!(kinds.contains(&"ChangeVisibility"));
        assert!(kinds.contains(&"AddDerive"));
        assert!(kinds.contains(&"RemoveDerive"));
    }

    /// Ensures all converter spec_kinds() are registered in MutationRegistry.
    /// This test prevents the "forgot to register" bug where a converter
    /// declares spec_kinds but they're not added to the registry.
    #[test]
    fn test_all_converter_spec_kinds_are_registered() {
        use std::collections::HashSet;

        let registry = MutationRegistry::new();
        let registered: HashSet<&str> = registry.registered_kinds().into_iter().collect();

        // Check IdiomConverter
        let idiom = converters::IdiomConverter::new();
        for kind in idiom.spec_kinds() {
            assert!(
                registered.contains(kind),
                "IdiomConverter::spec_kinds() contains '{}' but NOT registered in MutationRegistry. \
                Add: registry.register(\"{}\", Box::new(converters::IdiomConverter::new()));",
                kind, kind
            );
        }

        // Check RenameConverter
        let rename = converters::RenameConverter::new();
        for kind in rename.spec_kinds() {
            assert!(
                registered.contains(kind),
                "RenameConverter::spec_kinds() contains '{}' but NOT registered",
                kind
            );
        }

        // Check FieldConverter
        let field = converters::FieldConverter::new();
        for kind in field.spec_kinds() {
            assert!(
                registered.contains(kind),
                "FieldConverter::spec_kinds() contains '{}' but NOT registered",
                kind
            );
        }

        // Check EnumConverter
        let enum_conv = converters::EnumConverter::new();
        for kind in enum_conv.spec_kinds() {
            assert!(
                registered.contains(kind),
                "EnumConverter::spec_kinds() contains '{}' but NOT registered",
                kind
            );
        }

        // Check ModuleConverter
        let module = converters::ModuleConverter::new();
        for kind in module.spec_kinds() {
            assert!(
                registered.contains(kind),
                "ModuleConverter::spec_kinds() contains '{}' but NOT registered",
                kind
            );
        }

        // Check StmtConverter
        let stmt = converters::StmtConverter::new();
        for kind in stmt.spec_kinds() {
            assert!(
                registered.contains(kind),
                "StmtConverter::spec_kinds() contains '{}' but NOT registered",
                kind
            );
        }

        // Check DuplicateConverter
        let dup = converters::DuplicateConverter::new();
        for kind in dup.spec_kinds() {
            assert!(
                registered.contains(kind),
                "DuplicateConverter::spec_kinds() contains '{}' but NOT registered",
                kind
            );
        }
    }
}

#[cfg(test)]
mod tests_pre_check {
    use super::*;
    use ryo_analysis::testing::ContextBuilder;
    use ryo_source::pure::{
        PureEnum, PureField, PureFields, PureFile, PureItem, PureStruct, PureType, PureVariant,
        PureVis,
    };

    /// Create a simple PureFile with a struct
    fn make_test_file_with_struct(struct_name: &str, fields: &[(&str, &str)]) -> PureFile {
        let pure_fields = fields
            .iter()
            .map(|(name, ty)| PureField {
                name: name.to_string(),
                ty: PureType::Path(ty.to_string()),
                attrs: vec![],
                vis: PureVis::Public,
            })
            .collect();

        PureFile {
            attrs: vec![],
            items: vec![PureItem::Struct(PureStruct {
                name: struct_name.to_string(),
                vis: PureVis::Public,
                generics: Default::default(),
                fields: PureFields::Named(pure_fields),
                attrs: vec![],
            })],
        }
    }

    /// Create a simple PureFile with an enum
    fn make_test_file_with_enum(enum_name: &str, variants: &[&str]) -> PureFile {
        let pure_variants = variants
            .iter()
            .map(|name| PureVariant {
                name: name.to_string(),
                attrs: vec![],
                fields: PureFields::Unit,
                discriminant: None,
            })
            .collect();

        PureFile {
            attrs: vec![],
            items: vec![PureItem::Enum(PureEnum {
                name: enum_name.to_string(),
                vis: PureVis::Public,
                generics: Default::default(),
                variants: pure_variants,
                attrs: vec![],
            })],
        }
    }

    #[test]
    fn test_pre_check_rename_with_symbol_id() {
        use ryo_symbol::{SymbolKind, SymbolPath, SymbolRegistry};

        let registry = MutationRegistry::new();
        let file = make_test_file_with_struct("Config", &[("timeout", "u64")]);
        let ctx = ContextBuilder::new()
            .with_pure_file("src/lib.rs", file)
            .build();

        // Create a SymbolId (symbol_id is now required)
        let mut symbol_registry = SymbolRegistry::new();
        let path = SymbolPath::parse("test_crate::Config").unwrap();
        let symbol_id = symbol_registry.register(path, SymbolKind::Struct).unwrap();

        // Rename spec with required symbol_id
        let spec = MutationSpec::Rename {
            target: crate::executor::spec::MutationTargetSymbol::ById(symbol_id),
            to: "Settings".into(),
            scope: crate::executor::spec::Scope::Project,
        };

        // Pre-check is now a no-op for Rename (symbol_id is required, so no name-based lookup)
        let result = registry.pre_check(&spec, &ctx);
        assert!(
            result.is_ok(),
            "Pre-check should always pass for Rename with symbol_id: {:?}",
            result
        );
    }

    #[test]
    fn test_pre_check_add_field_with_symbol_id() {
        use ryo_symbol::{SymbolKind, SymbolPath, SymbolRegistry};

        let mutation_registry = MutationRegistry::new();
        let file = make_test_file_with_struct("Config", &[("timeout", "u64")]);

        // Create a SymbolId (pre_check doesn't verify it exists in ctx)
        let mut symbol_registry = SymbolRegistry::new();
        let path = SymbolPath::parse("test_crate::Config").unwrap();
        let symbol_id = symbol_registry.register(path, SymbolKind::Struct).unwrap();

        let ctx = ContextBuilder::new()
            .with_pure_file("src/lib.rs", file)
            .build();

        let spec = MutationSpec::AddField {
            target: crate::executor::spec::MutationTargetSymbol::ById(symbol_id),
            field_name: "name".into(),
            field_type: "String".into(),
            visibility: crate::executor::spec::Visibility::Pub,
        };

        // pre_check for AddField is now a no-op since symbol_id is required
        let result = mutation_registry.pre_check(&spec, &ctx);
        assert!(
            result.is_ok(),
            "Pre-check should always pass for AddField with required symbol_id: {:?}",
            result
        );
    }

    #[test]
    fn test_pre_check_add_variant_always_passes() {
        // AddVariant has required symbol_id, pre_check always passes
        let registry = MutationRegistry::new();
        let file = make_test_file_with_enum("Status", &["Active", "Inactive"]);
        let ctx = ContextBuilder::new()
            .with_pure_file("src/lib.rs", file)
            .build();

        // Get the enum's SymbolId from registry
        let enum_id = ctx
            .registry()
            .iter()
            .find(|(_, path)| path.name() == "Status")
            .map(|(id, _)| id)
            .expect("Status enum should exist");

        let spec = MutationSpec::AddVariant {
            target: crate::executor::spec::MutationTargetSymbol::ById(enum_id),
            variant_name: "Pending".into(),
            variant_kind: crate::executor::spec::VariantKind::Unit,
        };

        let result = registry.pre_check(&spec, &ctx);
        assert!(
            result.is_ok(),
            "Pre-check should always pass for AddVariant with required symbol_id: {:?}",
            result
        );
    }

    #[test]
    fn test_pre_check_add_derive_with_symbol_id() {
        use ryo_symbol::{SymbolKind, SymbolPath, SymbolRegistry};

        let registry = MutationRegistry::new();
        let file = make_test_file_with_struct("Config", &[("timeout", "u64")]);
        let ctx = ContextBuilder::new()
            .with_pure_file("src/lib.rs", file)
            .build();

        // Create a SymbolId (symbol_id is now required)
        let mut symbol_registry = SymbolRegistry::new();
        let path = SymbolPath::parse("test_crate::Config").unwrap();
        let symbol_id = symbol_registry.register(path, SymbolKind::Struct).unwrap();

        let spec = MutationSpec::AddDerive {
            target: crate::executor::spec::MutationTargetSymbol::ById(symbol_id),
            derives: vec!["Debug".into(), "Clone".into()],
        };

        // Pre-check is now a no-op for AddDerive (symbol_id is required)
        let result = registry.pre_check(&spec, &ctx);
        assert!(
            result.is_ok(),
            "Pre-check should always pass for AddDerive with symbol_id: {:?}",
            result
        );
    }

    #[test]
    fn test_pre_check_add_item_no_check_needed() {
        let registry = MutationRegistry::new();
        let file = make_test_file_with_struct("Config", &[]);
        let ctx = ContextBuilder::new()
            .with_pure_file("src/lib.rs", file)
            .build();

        // AddItem doesn't need pre-check (it adds new items)
        let spec = MutationSpec::AddItem {
            target: crate::executor::spec::MutationTargetSymbol::ByPath(Box::new(
                crate::executor::spec::SymbolPath::parse("test_crate").unwrap(),
            )),
            content: "struct NewStruct {}".into(),
            position: crate::executor::spec::InsertPosition::Bottom,
        };

        let result = registry.pre_check(&spec, &ctx);
        assert!(result.is_ok(), "AddItem should not require pre-check");
    }
}